The bogie is one of the most important components in the structure of the railway vehicle, it is mainly used to increase the carrying capacity, the length and the volume of the vehicle, and to increase the speed of the vehicle, such that the vehicle can have a good operation quality when it is run at a low or high speed under a specified railway track so as to protect the vehicle and the goods, satisfying requirements for the development of railway transportation. The bogie may be divided into a frame type bogie, a quasi-frame type bogie and a three-piece bogie in terms of the load transforming manner between the vehicle body and the bogie.
Referring to FIGS. 1 to 3, FIG. 1 and FIG. 2 are a front view and a top view of a side frame of a three-piece bogie in the prior art, respectively; and FIG. 3 is a structural schematic view of a supporting seat in FIG. 1. Operation processes of the above bogie and its drawbacks will be briefly explained hereinafter.
In the prior art, as shown in FIGS. 1 to 3, the above side frame is applicable to a central cross-braced bogie, that is, the bogie includes a first connecting rod and a second connecting rod passed through holes provided on two sides of the abdominal portion of the bolster in a cross manner, and each of two side frames thereof is symmetrically provided with two supporting seats 1′. During the operation, the two supporting seats 1′ of the first side frame are connected to the first end of the first connecting rod and the first end of the second connecting rod, respectively, and the two supporting seats 1′ of the second side frame are connected to the second end of the first connecting rod and the second end of the second connecting rod, respectively, so as to form the central cross-bracing structure and avoid a parallelogram phenomenon among the two side frames and two pairs of wheels. Therefore, the curving performance is improved and the critical speed of the hunting motion is increased.
However, the supporting seat 1′ on the above side frame includes a supporting plate 11′ which is arranged horizontally and a first vertical plate 12′ and a second vertical plate 13′ which are arranged vertically. The three plates are welded onto the side frame after being welded together. This kind of side frame has a high requirement on the welding process and a high dependence on the welding quality. A large deformation may be caused by welding, which generally results in a low installation precision of the side frame, and thus a poor strength of the side frame, which thereby affects the motion reliability of the bogie.
In view of the technical drawbacks in the prior art, there is an urgent demand to further improve the side frame of the bogie to increase the installation precision of the side frame and enhance the motion reliability of the bogie.